diff options
| -rw-r--r-- | Documentation/config.txt | 13 | ||||
| -rw-r--r-- | Documentation/git-receive-pack.txt | 13 | ||||
| -rw-r--r-- | builtin/receive-pack.c | 89 | ||||
| -rwxr-xr-x | t/t5541-http-push-smart.sh | 9 |
4 files changed, 112 insertions, 12 deletions
diff --git a/Documentation/config.txt b/Documentation/config.txt index dd6fd65..d73366f 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -2049,6 +2049,19 @@ receive.certnonceseed:: a "nonce" protected by HMAC using this string as a secret key. +receive.certnonceslop:: + When a `git push --signed` sent a push certificate with a + "nonce" that was issued by a receive-pack serving the same + repository within this many seconds, export the "nonce" + found in the certificate to `GIT_PUSH_CERT_NONCE` to the + hooks (instead of what the receive-pack asked the sending + side to include). This may allow writing checks in + `pre-receive` and `post-receive` a bit easier. Instead of + checking `GIT_PUSH_CERT_NONCE_SLOP` environment variable + that records by how many seconds the nonce is stale to + decide if they want to accept the certificate, they only + can check `GIT_PUSH_CERT_NONCE_STATUS` is `OK`. + receive.fsckObjects:: If it is set to true, git-receive-pack will check all received objects. It will abort in the case of a malformed object or a diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt index 2d4b452..9016960 100644 --- a/Documentation/git-receive-pack.txt +++ b/Documentation/git-receive-pack.txt @@ -89,6 +89,19 @@ the following environment variables: "git push --signed" sent a bogus nonce. `OK`;; "git push --signed" sent the nonce we asked it to send. +`SLOP`;; + "git push --signed" sent a nonce different from what we + asked it to send now, but in a previous session. See + `GIT_PUSH_CERT_NONCE_SLOP` environment variable. + +`GIT_PUSH_CERT_NONCE_SLOP`:: + "git push --signed" sent a nonce different from what we + asked it to send now, but in a different session whose + starting time is different by this many seconds from the + current session. Only meaningful when + `GIT_PUSH_CERT_NONCE_STATUS` says `SLOP`. + Also read about `receive.certnonceslop` variable in + linkgit:git-config[1]. This hook is called before any refname is updated and before any fast-forward checks are performed. diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 91d1a6f..efb13b1 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -43,6 +43,8 @@ static int prefer_ofs_delta = 1; static int auto_update_server_info; static int auto_gc = 1; static int fix_thin = 1; +static int stateless_rpc; +static const char *service_dir; static const char *head_name; static void *head_name_to_free; static int sent_capabilities; @@ -58,7 +60,10 @@ static const char *NONCE_UNSOLICITED = "UNSOLICITED"; static const char *NONCE_BAD = "BAD"; static const char *NONCE_MISSING = "MISSING"; static const char *NONCE_OK = "OK"; +static const char *NONCE_SLOP = "SLOP"; static const char *nonce_status; +static long nonce_stamp_slop; +static unsigned long nonce_stamp_slop_limit; static enum deny_action parse_deny_action(const char *var, const char *value) { @@ -145,6 +150,11 @@ static int receive_pack_config(const char *var, const char *value, void *cb) if (strcmp(var, "receive.certnonceseed") == 0) return git_config_string(&cert_nonce_seed, var, value); + if (strcmp(var, "receive.certnonceslop") == 0) { + nonce_stamp_slop_limit = git_config_ulong(var, value); + return 0; + } + return git_default_config(var, value, cb); } @@ -359,6 +369,8 @@ static char *find_header(const char *msg, size_t len, const char *key) static const char *check_nonce(const char *buf, size_t len) { char *nonce = find_header(buf, len, "nonce"); + unsigned long stamp, ostamp; + char *bohmac, *expect = NULL; const char *retval = NONCE_BAD; if (!nonce) { @@ -372,11 +384,67 @@ static const char *check_nonce(const char *buf, size_t len) goto leave; } - /* returned nonce MUST match what we gave out earlier */ - retval = NONCE_BAD; + if (!stateless_rpc) { + /* returned nonce MUST match what we gave out earlier */ + retval = NONCE_BAD; + goto leave; + } + + /* + * In stateless mode, we may be receiving a nonce issued by + * another instance of the server that serving the same + * repository, and the timestamps may not match, but the + * nonce-seed and dir should match, so we can recompute and + * report the time slop. + * + * In addition, when a nonce issued by another instance has + * timestamp within receive.certnonceslop seconds, we pretend + * as if we issued that nonce when reporting to the hook. + */ + + /* nonce is concat(<seconds-since-epoch>, "-", <hmac>) */ + if (*nonce <= '0' || '9' < *nonce) { + retval = NONCE_BAD; + goto leave; + } + stamp = strtoul(nonce, &bohmac, 10); + if (bohmac == nonce || bohmac[0] != '-') { + retval = NONCE_BAD; + goto leave; + } + + expect = prepare_push_cert_nonce(service_dir, stamp); + if (strcmp(expect, nonce)) { + /* Not what we would have signed earlier */ + retval = NONCE_BAD; + goto leave; + } + + /* + * By how many seconds is this nonce stale? Negative value + * would mean it was issued by another server with its clock + * skewed in the future. + */ + ostamp = strtoul(push_cert_nonce, NULL, 10); + nonce_stamp_slop = (long)ostamp - (long)stamp; + + if (nonce_stamp_slop_limit && + abs(nonce_stamp_slop) <= nonce_stamp_slop_limit) { + /* + * Pretend as if the received nonce (which passes the + * HMAC check, so it is not a forged by third-party) + * is what we issued. + */ + free((void *)push_cert_nonce); + push_cert_nonce = xstrdup(nonce); + retval = NONCE_OK; + } else { + retval = NONCE_SLOP; + } leave: free(nonce); + free(expect); return retval; } @@ -426,6 +494,9 @@ static void prepare_push_cert_sha1(struct child_process *proc) if (push_cert_nonce) { argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE=%s", push_cert_nonce); argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_STATUS=%s", nonce_status); + if (nonce_status == NONCE_SLOP) + argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_SLOP=%ld", + nonce_stamp_slop); } proc->env = env.argv; } @@ -1361,9 +1432,7 @@ static int delete_only(struct command *commands) int cmd_receive_pack(int argc, const char **argv, const char *prefix) { int advertise_refs = 0; - int stateless_rpc = 0; int i; - const char *dir = NULL; struct command *commands; struct sha1_array shallow = SHA1_ARRAY_INIT; struct sha1_array ref = SHA1_ARRAY_INIT; @@ -1396,21 +1465,21 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix) usage(receive_pack_usage); } - if (dir) + if (service_dir) usage(receive_pack_usage); - dir = arg; + service_dir = arg; } - if (!dir) + if (!service_dir) usage(receive_pack_usage); setup_path(); - if (!enter_repo(dir, 0)) - die("'%s' does not appear to be a git repository", dir); + if (!enter_repo(service_dir, 0)) + die("'%s' does not appear to be a git repository", service_dir); git_config(receive_pack_config, NULL); if (cert_nonce_seed) - push_cert_nonce = prepare_push_cert_nonce(dir, time(NULL)); + push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL)); if (0 <= transfer_unpack_limit) unpack_limit = transfer_unpack_limit; diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh index 24926a4..ffb3af4 100755 --- a/t/t5541-http-push-smart.sh +++ b/t/t5541-http-push-smart.sh @@ -340,21 +340,26 @@ test_expect_success GPG 'push with post-receive to inspect certificate' ' SIGNER=${GIT_PUSH_CERT_SIGNER-nobody} KEY=${GIT_PUSH_CERT_KEY-nokey} STATUS=${GIT_PUSH_CERT_STATUS-nostatus} + NONCE_STATUS=${GIT_PUSH_CERT_NONCE_STATUS-nononcestatus} + NONCE=${GIT_PUSH_CERT_NONCE-nononce} E_O_F EOF - git config receive.certnonceseed sekrit + git config receive.certnonceseed sekrit && + git config receive.certnonceslop 30 ) && cd "$ROOT_PATH/test_repo_clone" && test_commit cert-test && git push --signed "$HTTPD_URL/smart/test_repo.git" && ( cd "$HTTPD_DOCUMENT_ROOT_PATH" && - cat <<-\EOF + cat <<-\EOF && SIGNER=C O Mitter <committer@example.com> KEY=13B6F51ECDDE430D STATUS=G + NONCE_STATUS=OK EOF + sed -n -e "s/^nonce /NONCE=/p" -e "/^$/q" push-cert ) >expect && test_cmp expect "$HTTPD_DOCUMENT_ROOT_PATH/push-cert-status" ' |